'It is unrealistic to assume that telling people they can’t go on the waiting list for a much-needed operation until they lose weight will yield any result except despair.' Photograph: Tony Gentile/Reuters

If you're overweight or you smoke, you won't be able to have your hip replaced or your gallbladder removed. Before being put on a waiting list, you'll have to make efforts to mend your wicked ways. That is what one consortium of GPs in Hertfordshire has decided. And with the government determined to save £60bn from the NHS, it's unlikely to be the last to agree to this kind of rationing of resources.

Fair enough, you may say. The risks of operations are reduced if you are slim and don't smoke. Obesity contributes to osteoarthritis of the hip and gallstones, as well as diabetes and high blood pressure. Every smoker in the land must know that they are running an increased risk of lung cancer, and lung and heart disease. Clearly, the risks of anaesthetic complications are higher if you're a heavy smoker or very fat. And why should slim, non-smoking taxpayers bear the cost of the lumpen puffers?

But this cannot be a defensible position. The Hertfordshire GPs are surely going to have to rethink. Their ruling will potentially affect nearly one quarter of all adults in their area (in 2009 22% of men and 24% of women in England were obese – with a body mass index over 30), and a third of women and nearly half of men if they include overweight people (with a BMI of 25-30). It is completely unrealistic to assume that telling people they can't go on the waiting list for a much-needed operation until they lose weight will yield any result except despair. Fat is a class issue nowadays. The richer you are, the less likely you are to be fat. Healthy food's expensive. The factors are complex, and responsibility lies with individuals, schools, health professionals, government and the food and advertising industries – not with a bunch of GPs flexing their commissioning muscle.

The same goes for smoking, although at least you can say you've quit smoking and, presumably, get your place on the waiting list. You can't wake up one day and decide to be slim.

There is no end to this judgmental view of healthcare rationing. Why can't the fat person have a gallbladder out when the alcoholic has a liver transplant? Why should we treat the sexually transmitted disease a man gets from a wild stag night in Amsterdam? What about the melanoma that develops after a lifetime of sunbathing? By all means educate, instigate screening, bring in public health measures to promote healthy living. But spare us this nasty, mean-spirited, discriminatory and frankly vindictive approach to "care".

But maybe you're reading this and feeling smug. You may be slim and a non-smoker, and feeling pretty good that if you ever need an operation, it'll be a shoo-in. With all the fatties, smokers and other pariahs excluded, waiting lists should be non-existent.

You may want to know about the extent of NHS rationing being enforced throughout the country. PoLCE stands for Procedures of Limited Clinical Effectiveness: a list of treatments you may find you can't get on the NHS in your area. It includes operations for piles, varicose veins (no matter how severe), hernias – and, in my part of London, tonsillectomy.

A 16-year-old girl who has had six documented episodes of severe tonsillitis in a year, was told by a local specialist that she needs to have her tonsils removed. She has missed weeks off school during an exam year and suffered educationally and socially. The procedure has been turned down. As her GP, I have appealed on her behalf. However, that was six months ago, and the appeal has not been heard yet, and is likely to be rejected.

Local GP commissioning groups are making their own decisions about how to implement the rationing that the government insists on. You may well be affected – even if you lead the most impeccable lifestyle and have the most honed body in the village. There's no room for complacency.